1. Field of the Invention
The invention relates to Direct Current (DC) power supplies, and in particular to DC to DC converters.
2. Background Information
Very large scale integration (VLSI) has resulted in the power consumption of integrated circuits increasing substantially. At the same time size and weight are vital considerations and thus it is desirable to increase the output of DC power supplies without increasing their size and weight. Operating power supplies at high switching frequencies allows the relative size of passive components such as inductors and capacitors to be reduced. However, high frequency switching of high converter currents can cause Electromagnetic Interference (EMI).
Switched-capacitor converters have been developed for fabrication in integrated circuits. This type of converter has no magnetic component for filtering so its size and weight are reduced. Energy is stored in the switched-capacitor. However, it has a problem with current spikes when charging the switched-capacitor. Electromagnetic interference (EMI) is produced by the current spikes.
When a semiconductor device such as a metal oxide semiconductor field effect translator (MOSFET) or Insulated gate bipolar transistor (IGBT) turns on or off in the presence of a current flow power (I2R) is consumed. This results in heating of the device and reduced efficiency. In a high frequency high power converter this heating and switching loss can become significant.